On its own, it means everything. With a noun it means all or whole. У меня всё I have everything я вижу всё окно I see the whole/all of the window
"До" means until, before, up to (and including). "К" means "by" when used with time expressions (by Sunday), to, towards, in the direction of. "До" takes genetive case, and "к" tales dative case.